The present invention relates generally to electrical connectors, and in particular to connectors for connection of coaxial transmission lines to etched circuit boards.
Automated semiconductor equipment has been developed for fast, efficient, and accurate dynamic testing of new semiconductor devices in a production setting. This equipment measures rise time, fall time, propagation delay, storage time, delay time, and performs other dynamic measurements on the semiconductor devices in order to provide a higher yield of salable devices than can be provided by performing static tests. Such semiconductor test equipment generally includes a plurality of replaceable plug-in probes to accommodate the testing of devices having a wide range of sizes and pin configurations. Typically, a probe largely comprises an etched circuit board with a probe head mounted thereon for receiving the semiconductor devices, and the interface of the probe with the test apparatus is made via conventional circuit board edge connectors. Because testing semiconductor devices frequently involves test signal having frequencies of up to about 700 megahertz and pulse rise times of as little as 500 picoseconds, coaxial cables are utilized to interconnect the process and control circuits of the test apparatus and the test probe. The center conductor of each coaxial cable carries the test signal, while the outer conductor provides a grounded shield.
Circuit board edge connectors provide an inexpensive and reliable method of signal connection. Hitherto, both the signal and ground connection of each cable have been connected via pins to the edge connector to the circuit board, one side of which carried signal paths, or runs, to the probe head and the other side of which provided a ground plane. However, with increasing semiconductor chip sizes and the increasing number of pins on the devices themselves, it is highly desirable to utilize both sides of the etched circuit board for signal runs and nearly all of the pins of the edge connector for signal connection.